topas

topas [-c filename] [-d interval] [-n iterations] [-p pidlist] [-s] [-u userlist] [-x file] [-X file] [-Y file]

-c filename
    Reads commands from the specified file.

-d interval
    Sets the update interval in seconds (default is 2 seconds).

-n iterations
    Specifies the number of iterations to run before exiting.

-p pidlist
    Monitors only processes with the specified process IDs (comma-separated list).

-s
    Runs in batch mode (non-interactive).

-u userlist
    Monitors only processes owned by the specified users (comma-separated list).

-x file
    Writes the collected data to the specified file in ASCII format.

-X file
    Writes the collected data to the specified file in binary format.

-Y file
    Writes the collected data to the specified file in CSV format.

The topas command is a performance monitoring tool for AIX and Linux systems.
It provides a dynamic, real-time view of system activity, including CPU utilization, memory usage, disk I/O, network activity, and process information. It displays a continuously updated list of the most CPU-intensive or memory-intensive processes, helping administrators identify performance bottlenecks and resource consumption patterns.
Topas is a crucial tool for system administrators and performance analysts to diagnose performance issues and optimize system resources. Unlike `top`, `topas` can sometimes provide more detailed AIX-specific metrics. The utility's interactive mode allows for filtering and sorting data, making it easier to pinpoint problem areas. Topas can be run interactively or in batch mode for data collection and analysis.
The collected data can be analyzed to identify trends and patterns in resource usage, enabling proactive system optimization.

When running topas interactively, you can use commands like 'c' to sort by CPU, 'm' to sort by memory, and 'k' to kill a process. Refer to the topas documentation for a complete list of interactive commands.

Understanding the topas output requires familiarity with system performance metrics. Key metrics include CPU utilization (user, system, idle, wait), memory usage (free, used, cached), disk I/O (read, write), and network activity (packets in/out). Interpreting these metrics allows you to identify bottlenecks such as high CPU load, memory pressure, or disk I/O saturation.

Topas was specifically developed for AIX systems to provide a more comprehensive system monitoring tool than the standard `top` command. Its development was focused on incorporating AIX-specific kernel statistics and features.
The command has been continuously improved over the years to include new metrics and features, and has been ported to Linux, maintaining its core functionality of providing real-time system performance monitoring. Initially it was designed to address shortcomings in existing monitoring tools on AIX.
The tool is used by system administrators to diagnose performance issues, optimize resource allocation, and troubleshoot system problems.

top(1), vmstat(8), iostat(1), ps(1)